154
THE COUNTY’S INFRASTRUCTURE BACKBONE
PLANNING ISSUE
How do we manage
stormwater in a way that
restores predevelopment
hydrology, reduces flooding,
recharges groundwater, and
improves water quality in
compliance with state
programs and within existing
budget constraints?
Sewage Facilities
Water Facilities
Solid Waste
Stormwater Management
Energy
Communications
Emergency Services
Other Governmental Facilities
Stormwater Management
Stormwater is often seen in terms of flooding. However, it is
part of a larger process – the hydrologic cycle – that cleans
and distributes water and has a significant impact on the
environment, people’s lives, and the economy. Protecting
and restoring site hydrology minimizes impacts to public
water supply and ecosystems. Managing stormwater on a
watershed basis reduces flooding. Using stormwater Best
Management Practices (BMPs) protects water resources.
Land in a natural state produces little runoff. Rainfall is
absorbed and slowly released to groundwater, surface waters
and the atmosphere. Vegetation loss, impervious surfaces,
and soil compaction from development disrupt site
hydrology and greatly increase runoff. Maintaining natural
drainage on a site during and after development minimizes
this disruption. Stormwater BMPs can preserve and restore
site hydrology during development.
Flooding is an issue that involves zoning and land use,
stormwater management, and flood plain regulation. Land
use regulations often require large basins be installed at a
site’s lowest point to manage all the runoff from a
development. Over the past few years, there has been a
move to a more dispersed strategy that manages stormwater
close to its source. Used in tandem and located close to the
point of generation, stormwater BMPs have been shown to
be more effective than the single basin strategy in mitigating
local flooding.
Two state programs that influence stormwater management
are the
program and Phase
II of the NPDES program, often referred to as the
program. Act 167 requires counties to prepare watershed-
based stormwater management plans for designated
watersheds. Through the watershed approach, upstream
control in one municipality resulting in downstream flooding
in another municipality is avoided. The county has
completed plans for 10 of its 17 watersheds; a county-wide
plan is being considered to complete the remaining plans and
update the existing ones. The MS4 program requires the
county to develop a stormwater program to address
stormwater discharges from county facilities.
What’s New
•
—Pennsylvania revised and reissued the MS4
permit requirements in 2011. The Municipal
Separate Storm Sewer (MS4) program requires the
county to manage runoff from county-owned sites.
The county’s stormwater program must include:
−
Education and Outreach
−
Staff Participation
−
Illicit Discharge Detection and Elimination
−
Stormwater Management During Construction
−
Post-Construction Stormwater Management
−
“Good Housekeeping” in County Operations
•
Stormwater BMPs
(BMPs) treat stormwater as a resource. BMPs are
replacing the “one large basin” strategy. Many
smaller BMPs are being used in tandem, close to
where the runoff is forming. BMPs include:
−
Naturalized basins
−
Reduced or disconnected impervious surfaces
−
Rain gardens
−
Porous pavement
−
Infiltration basins or trenches
−
Sediment forebays
−
Stormwater ponds
−
Constructed wetlands
•
—Stormwater plans were adopted
in 2011, in compliance with Act 167, the
Pennsylvania Stormwater Management Act for these
watersheds:
−
Tookany-Tacony/Frankford watershed
−
Valley Creek watershed
−
Headwaters of the Perkiomen
−
Pennypack watershed
•
The county has developed a model floodplain
ordinance that municipalities can adopt to maintain
compliance with the National Flood Insurance
Program. The ordinance can be found on the county
planning commission website.
